The Federal Communications Commission yesterday deferred a final decision on whether to move its headquarters and 1,600 employes from downtown Washington to Rosslyn until the agency receives a new chairman.

"In my judgment, this kills . . . the possibility of moving to Virginia," said acting FCC Chairman Robert E. Lee. He said that after yesterday's vote space in Arlington that had been held from the market in anticipation of the move was immediately placed on the market.

"In my judgment," Lee said, "that's the end of that." He said he expected the 300,000-square-foot block of space to be rented quickly in smaller segments.

An FCC spokesman said that a vote on the relocation, dubbed "Project Exodus" by its supporters, is unlikely before mid-April. The commission agreed yesterday to extend for at least two weeks the time for developers to submit other office space proposals.

Last month, despite objects by some city officials and members of Congress, the commission voted to lease 22 floors of the 30-story Twin Towers high-rise in Arlington. Two weeks later, the agency reluctantly agreed to consider a proposal by a downtown Washington developer who offered to lease office space at a price the developer said was comparable to the rent the FCC expects to pay in Virginia.

Some officials have criticized the move, saying that the federal government should not be moving into skyscrapers which the Interior Department unsuccessfully opposed in court on the grounds that the buildings would mar the Washington skyline.